UPS Suggestions for my 550w System

[JbrRo]

I live in the Philippines, a country where power outages and interruptions are a regular occurrence. So recently, i've been reading up on Uninterruptible Power Supplies (UPS). I just bought a new system with the specs below and i would appreciate any advice on what type and capacity UPS i should get. Thank you in advance!

CPU
i7-4790K
MOTHERBOARD
Gigabyte z97x Gaming 3
RAM
G.Skill RipJaws X (Dual) 2X8gb ddr3 1866 CL9 ( F3 1866C9D 16GXM )
PSU
Seasonic G550 80+ Gold Modular
GPU
Gigabyte 970 G1 Gaming 4gb
Case
Fractal Define R4
Drives
WDC 1tb Scorpio Blue (WD10JPVX) 8mb sata
Samsung SSD 840 250gb
Seagate 500gb
MONITOR
22" Samsung TV

 

[atheus]

UPS's are a bit of a bothersome subject for me. Standard wisdom says that if you have an Active PFC PSU (which you do) you need to get a pure sine wave UPS for it to run properly off of the inverter in the UPS. That's not always true, but sometimes it is - depending on the hardware involved. Some UPS's will output AC in what's called a "square wave" which is a wave shaped like |_|‾|_|‾| - this is not a nice smooth transition from -1 to +1 on the graph. Less terrible UPS's will output a "modified square wave" or a "stepped square wave" which has some intermediate steps between -1 and +1 which make it look a bit more like a sine wave, but you're still working with 90 degree bends in the wave form. The best UPS's output a "pure sine wave" which is more or less exactly like the nice smooth power you get from your AC wall outlet, and will work with 100% of AC devices.

The problem with square waves or stepped square waves with Active PFC PSU's (like yours) is that your system may or may not just shut down as soon as the UPS swaps over to battery. The plus side is that they're about half as expensive as pure sine wave PSU's. The minus side is that there's no good way to know whether it will work or not until you try, unless you can happen to find a forum discussion somewhere with someone who has your exact PSU. I can tell you that I have a Seasonic X series 560 w PSU and it does work with a APC Back-UPS XS 1500 which generates a stepped square wave... most of the time. I have had it crash instantly on battery a few times out of dozens and dozens of power events.

If you have the money, the best choice is probably an APC Smart-UPS SMC1000 or SMC1500 (depending on how many other devices you need to run on battery) which does the pure sine wave output that is guaranteed to work with any PSU without harming it.